Force MimeHandlerView to always use BrowserPlugin

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 1fb9201c58d29fbde43c47ce8305b46c99893df0..09ecf05b24e71fb9505ecd28d4e08d6f2195b34c 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1538,6 +1538,7 @@ void WebContentsImpl::Init(const WebContents::CreateParams& params) {
 
   if (!view_) {
     if (browser_plugin_guest_ &&
+        !browser_plugin_guest_->IsMimeHandlerViewGuest() &&
         BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
       view_.reset(new WebContentsViewChildFrame(
           this, delegate, &render_view_host_delegate_view_));
@@ -1548,7 +1549,8 @@ void WebContentsImpl::Init(const WebContents::CreateParams& params) {
   }
 
   if (browser_plugin_guest_ &&
-      !BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
+      (!BrowserPluginGuestMode::UseCrossProcessFramesForGuests() ||
+       browser_plugin_guest_->IsMimeHandlerViewGuest())) {
     view_.reset(new WebContentsViewGuest(this, browser_plugin_guest_.get(),
                                          std::move(view_),
                                          &render_view_host_delegate_view_));
@@ -4558,7 +4560,10 @@ void WebContentsImpl::EnsureOpenerProxiesExist(RenderFrameHost* source_rfh) {
     // then we should not create a RenderView. AttachToOuterWebContentsFrame()
     // already created a RenderFrameProxyHost for that purpose.
     if (GetBrowserPluginEmbedder() &&
-        BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
+        BrowserPluginGuestMode::UseCrossProcessFramesForGuests() &&
+        !(source_web_contents->browser_plugin_guest_ &&
+          source_web_contents->browser_plugin_guest_
+              ->IsMimeHandlerViewGuest())) {
       return;
     }
 
@@ -4961,12 +4966,14 @@ RenderFrameHostManager* WebContentsImpl::GetRenderManager() const {
 }
 
 WebContentsImpl* WebContentsImpl::GetOuterWebContents() {
-  if (BrowserPluginGuestMode::UseCrossProcessFramesForGuests()) {
+  if (BrowserPluginGuestMode::UseCrossProcessFramesForGuests() &&
+      (!browser_plugin_guest_ ||
+       !browser_plugin_guest_->IsMimeHandlerViewGuest())) {
     if (node_)
       return node_->outer_web_contents();
   } else {
-    if (GetBrowserPluginGuest())
-      return GetBrowserPluginGuest()->embedder_web_contents();
+    if (browser_plugin_guest_)
+      return browser_plugin_guest_->embedder_web_contents();
   }
   return nullptr;
 }